Abstract: On-line fault location distance measurement is very important for fault detection and repair of urban 10 kV cable lines. Because of the complex structure of distribution lines, the existing single-terminal or double-terminal traveling wave location technology for measuring distance cannot be directly appliedIt is impossible to locate the fault point accurately, check and repair it quickly, which brings certain inconvenience and economic loss to residents′ life and enterprise production. In this study, the characteristics of voltage and current traveling wave and the refraction and reflection laws in a typical 10 kV cable network are analyzed when grounding fault occurs, particularly in the ring cabinet and at the end of the line.This paper presents the system structure and working principle of a distributed fault traveling wave ranging system installed in the ring network cabinet and the end of the line, as well as the key technologies such as high-speed data acquisition, sensor acquisition frequency band selection and the end of the line current traveling wave acquisition method,The reliability and accuracy of the technology and system are verified using several field examples.

Key words: cable network, low-current grounding, traveling wave, fault location, distributed fault